Collapsible stairway



Aug. 11,1936.

C. TRAUT COLLAPSIBLE STAIRWAY Filed July 15, 1953 s sheets-sheet 1WMWOR' ATTORNEYS.

Aug. 11, 1936.

c. TRAUT COLLAPS IBLE STAIRWAY Filed July 15, 1953 3 Sheets-Sheet 2ATTORNEY.

1N VEN TOR Aug. 11, 1936. C. TRAUT 2,050,593

COLLAPS IBLE STAIRWAY Filed July 13, 1955 s sheets-sheet 5 Patented Aug.11, 1936 UNITED STATES PATENT GFFlCE COLLAPSIBLE STAIRWAY Cliiord Traut,Newport, Ky., assgnor to The Higgin Manufacturing Company, Newport, Ky.,

12 Claims.

My invention relates to stairways, and more especially to stairways inwhich-a step-supporting structure is collapsible into a iioor opening orhatchway or extensible down therefrom toward 5.1 the lower floor.

An object of my invention is to provide a device'of this character whichis of simple and light," yet rugged construction, safe, and easy tooperate into and out of extended condition. An

4': especial object is'to yprovide such a device to 1li; hatchway, oritsextensiondownwardly as the door is opened. A further especial object isto provide a simple, compact and safe means for counterbalancing thestairway for ease of operation into and out of its extended condition.

2Q., Other-objects will appear in the course of the followingdescription, illustrated bythe accompanying drawings,in which- Figure 1is a side elevation of' a stairway embodying my invention, parts of thefloors and ythe-hatchway door being in vertical section.

Figure 2 is a partial sectional plan view of thesame, the section beingon the line 2-2 ofl Figure l 'through the upper iloorA structure abovethe'stairway structure.

Figure 3 isian enlarged front elevation of the stairwaystructure'withpart ofthe upper floor structure in cross section onV the lineS-B ofFigure 1,1 and intermediate parts of the stairway structure broken awayand omitted for lack of space;

Figuree-is'fa vertical iront to rear section on the same scale, of'theupper part of same, on the line 4 4 voi Figure 3, the closedposition ofthe-door and position of the collapsed stairway i being indicated bydotted lines.

Figure-5 isa similar section of the lower end part ofl the stairway inits extended condition.

Figure 6is a detailed view of a portion Iof1 ai step.- i "1W Broadlystated, my invention comprises a pair of'transversely spaced lazy-tongstringers, links of whichY have respective stair steps mounted on them;with crossing diagonal strutsbracing the stri-ngers'laterallyinconjunction with the steps;

50A track means mounted on the hatchway door in which the'lower jointsof the lazy-tong stringers ride upon rollers; a connection of the Alastupper links fofetheilazy-tong stringere to the hatchway rear wall abovethe door hinge; and a counter- 5.5balancing'device, preferably a pairofvtensioll springs, mounted within the upper floor structure andconnected through the hatchway rear wall with certain links of thelazy-tong stringers by cables.

To limit the extension of the stairway structure, certain of its linksare made to engage stops on the hatchway side walls; and to render thecoaction of the door and stairway structure easy, and to avoid thenecessity of very accurate design of the parts, the track on the door ismade movable thereon so that while it guides the collapsing andextending stringers, it adjusts itself to them in their collapsedcondition. When extended, the lower end of the structure rests on thelower floor, and the limiting stop mentioned above prevents the slidingof the lower end on the floor to a more extended position. Thecounterbala'nce is suiiicientV to render the device easy Vof operationwithout entirely overcoming its weighi'qso that when extended the devicerests iirrnly on the lower floor. The door is latched or otherwisesuitably held in its raised, closed position,v and 'supports thecollapsed stairway.

In my preferred construction, as shown in the drawings", my device is.provided in conjunction with the lower floor I and upper iioor 2Y of abuilding; the upper floor having an opening or hatchway 3 formed betweentwo joists of the iioor,'which form the side walls 4 with shortcross-joists forming the rear and front walls 5 and 6, respectively, ofthe hatchway. The hatchway door 'I is hinged at 8 to the lower edge' ofthe rear wall 5, and at its front edge has a suitable latch 9 coactingwith a stirrup I0 on the lower edge ofthe iront wall 6. This is a usualconstruction and is explained merely to facilitate the disclosure ofthev relation of my invention thereto.

Each lazy-tong Stringer comprises a series of pairs of step links II andriser links I2 which cross each other and are connected at theircrossings by pivots I3.` Pivots I4 and I5 connect the ends of thesuccessive pairs of links II and I2. Considering either Stringer in itsdownwardly inclined position, the lowest pair of links II and I2 havetheir lower ends connected byv pivots I8 and i'I to the upper ends of afoot link I8 anda short step' link I8, which latter has its lower endconnected to an intermediate part oi foot link I8 by a pivot 20;" Thefoot link I is an angle bar, and its lower end rests on the lower iioorI.r

The upper ends of the uppermost pair of links I I and I2 are connectedby'pivots' ZI and 22 to an additional pair of step and riser links IIaand I2a, respectively. These links are connected, where they cross eachother, by a pivot I3a. The upper end of step link IIa is connected bypivot 23 to a short link 24, the upper end of which is connected bypivot 25 to the terminal step link 26, in an intermediate part thereof.One end of this step link 26 is connected by a pivot 21 to the upperpart of riser link I 2a, which extends above the pivot 21 and has itsyupper end offset outward and bent downward, forming a hook 28. The otherend of the terminal step link 26 is connected by pivot 29 to an anchorbracket 30 fixed on the rear wall 5 of the hatchway 3.

The step links I9, Il, Ila, and 26 of the two stringers lie at the innersides of the riser links, and. the steps 3! are mounted on respectivepairs; of these step links at such an angle in front to rear extent thateach step lies approximately horizontal when the stringers are in theirinclined extended position. Each step preferably consists of a platebent to channel shape with its flanges 32 depending along itslongitudinal edges, and having at its ends ears 33 and 34 bent down nearthe front and up near the rear, respectively. The front bent down ear 33is held by the crossingr pivot 20, I3, |30. or 25, as the case may be,and the rear bent up ear is riveted to the respective step link. Eachstep 3| thus is in effect unitary with a pair of step links. The cornersof the step flanges 32 are cut away at 35.

To stiffen the stair structure transversely, in

addition to the stiffening afforded by the steps 3|, diagonal braces 36have ears 31 and 38 at their ends, and a crossing pair of these isprovided at each step. Each brace has one end ear 31 connected to thepivot I3, I 3a or 25 at the -front ear of the step, and its opposite endear such truss, the two trusses being pivoted to swing relatively forthe lazy-tongs action, with the steps swinging downwardly and forwardlyin back of the respective pairs of braces 36 when the lazy-tongsstructure folds up as shown by the dotted lines in Figure 4. The footlinks I8, in their extensions below the pivots 2n. are connected andrigidly braced by a transverse strut 40 with its ends riveted to thelower end parts of the inturned members of these links, and diagonalbraces 4I riveted to the upper parts of these inturned members and tothe strut 40.

The bottom pivots I1, I5. 22 and 23 of the lazy-tong stringers havelaterally outward extensions carrying rollers 42, spaced out from theriser links. On the upper side of the hatchwav door 1, close to andparallel with the resnective lateral edges thereof, track members 43 aremounted, each in the form of a channel opening inwardly, with itsflanges turned in toward each other at their inner edges, formingretaining beads 44. These channel flanges and their beads 44 flareoutwardly at the lower ends 45 of the members 43 for ready entrance ofthe rollers 42 to the channels. These track members 43 are not fixed tothe door 1, but merely are connected thereto by hinges 36 attheir endsnear the front edge of the door. When the stairway structure is extendedthe three upper ones of the rollers 42, in the example as shown, remainin the track member 43 at each side. When the stairway structure iscollapsed, the other lower rollers 42 enter these track members. Thebeads 44 hook inside the rollers 42 which are in the track members, sothat the track members and lazy-tongs structure are retained inoperative relation with respect to lateral displacement.

Hook brackets 41 are fixed on the side walls 4 of the hatchway, openingupwardly, at such location as to receive the hooks 28 of the upper endsof the extended riser links 52a, before described, when the lazy-tongsstairway structure is extended into its lowered position. The engagementof these hooks 28 with the hook brackets 41 limits the extension of thestructure, and in conjunction with the engagement of the bottoms of thefoot links I8 with the lower floor I, prevents forward slippage of thestairway structure under the load on the steps. With their extensionthus limited, the lazy-tong stringers constitute trusses effective invertical planes, and the assembly of cross braces 35 and riser links,and steps 3I and step links, constitute trusses effective in transverseplanes. The extended structure therefore is very rigid againstdeflection either in a vertical or a transverse direction.

As the entire extensible structure is rather heavy, and the friction inits numerous pivot joints also offers considerable resistance tocollapsing, I provide a suitable counterbalancing device. As hereinshown, this device includes a pair of tension springs 48, seen inFigures 1 and 2, within the upper floor structure to the rear of thehatchway 3. The rear ends of these springs 48 connect to eye bolts 49extending through blocks 5D built into the floor structure as shown. Thejoist piece forming the rear wall 5 of the hatchway has suitableapertures 5I and cables 52 connected to the front ends of the respectivesprings 48 pass over grooved rollers 53 mounted on the back of the joistpiece, and pass out forwardly through the respective apertures 5I andhave their forward ends connected to studs 54 xed in and extending outfrom the outer sides of the respective riser links I 2a up from thelower ends thereof far enough to clear the tops of the track members 43.The springs 48 are so made and adjusted that they counter balance mostbut not all of the weight of the extensible structure in addition toovercoming the friction of its pivot joints. The structure thus willextend downwardly by gravity, but may be pushed up into collapsedcondition with ease.

It will be understood that the operator may raise the structure first bydirectly engaging it with the hand, and then in the higher stages,engage it with a suitable pusher rod, pole or the like, which also maybe used to operate the door 1 and latch 9. The cables 52 might beconnected at any point to the risers I 2a, or to any point of any otherriser, or to any of the step links, and the springs would be effectiveon the structure. I prefer to make the lower connection because, as willbe seen by the dotted lines in Figure 4, the cables 52 have a materialupward slant over the rollers 53 when the device is collapsed and thedoor 1 closed. This is effective to cause a not too sudden drop of thedoor 1 underthe weight ofthe device, when the 'latch 9 is released. Byconnecting the cables to one of the upper pairs of links, the necessarytravel of the cables isminimi-zed, calling for strong springs but withrelatively little. required extension, which isrnost favorable` to theuse of springs.

It will be noted that the device collapses to a length much less thanthat of the door 1, so that it amply clears the front 6 of the hatchway3 in opening and closing. As the lazy-tongs sleepers Yare connectedtothe door by their rollers-42 and the track members 43, and areconnected to the hatchway rear wall by terminal step link- 26 andbracket 30, the motion of the door is imparted in some degree to theextensible structure, so that extension and collapse of the latter isaccompanied by the door opening and closing, respectively. The result isa more continuous and rapid action of the structure and doorcollectively, either in opening or in closing. This connection of door,stairway structure and upper floor structure also relieves the doorhinge 8 of most of the strain of supporting the stairway structure,either in collapsed or extended condition.

By using springs instead of weights, for instance, I am able to make theentire device very compact, without any excessive extensions from thefloor or hatchway, avoiding obstruction to free passage and storage inthe vicinity of the device, The connection of the counterbalancingdevice to an upper part of the collapsible structure also avoids thetendency to distort the structure that is present with connection to thelower part thereof, in addition to reducing the necessary range ofaction of the counterbalancing device as before mentioned.

Owing to the advantageous disposition of the parts, in respect ofbracing in the vertical and transverse planes as before mentioned, andto the easy action of the counterbalance on the structure, the parts maybe relatively light and of simple formation. This, of course, results ineconomy of manufacture as well as ease of operation. The track members43 being hinged to the door 1, can adjust to any slight discrepancy ofrelative position of the lazy-tongs structure and door in closed,collapsed condition, as seen at A in Figure 4. This avoids necessity ofvery accurate design and installation of the apparatus. It is preferablethat the track members 43 should bear firmly on the door when the deviceis opened and extended, as indicated in Figure 4 at B.

This is easily accomplished, and the proper coaction of hook members 28and 41 is assured by installing members 3l! and 41 on the hatchway wallswhile the stairway structure is extended and resting on the lower oor I,after first connecting the track members 43 by their hinges 45, to thedoor, swinging these members 43 onto the door, and inserting the upperrollers 42 into the track members. The counterbalancing apparatus, ofcourse, requires removal of the boards of upper floor 2, for installingit; ,and this is conveniently done when the device is in closed,collapsed condition, adjusting the springs to the required initialtension by the eye bolts 49.

It will be understood that various modifications may occur, and that Iam not limited to the precise disclosure herein; but having thus fullydescribed a preferred example of my invention, what I claim and desireto secure by Letters Patent, is:

1. Ina collapsible stairway, longitudinally collapsible stringers, stepscarried by said stringers, means pivotally anchoring said stringers atone end of the stairway, and means-movable relatively to the anchoragemeans,`forming a guide for the stringers as they collapse, andsupporting the stairway in its collapsed condition.

2. In a collapsible stairway, longitudinally collapsible stringers,steps carried by said stringers, means pivotally anchoring saidstringers at one end of the stairway, and means supporting the stairwayin its collapsed condition comprising a guide, and means moving with thestringers and guided in said guide. Y

3. In a collapsible stairway, longitudinally collapsible stringers,steps carried by said stringers, means pivotally anchoring saidstringers at one end of the stairway, and means supporting theV stairwayin its collapsed condition comprising a guide, and means moving with thestringers and guided in said guide, said guide being movably connectedto said supporting means to adjust to the stairway when the latter iscollapsed.

4. In a collapsible stairway, longitudinally collapsible stringers,steps carried by said stringers, means pivotally anchoring saidstringers at one end of the stairway, and means supporting the stairwayin its collapsed condition comprising a guide, and means moving with thestringers and guided in said guide, said guide being movably connectedtoy said supporting means to adjust to the stairway when the latter iscollapsed, and said guide and said guided means having mutual engagementto limit relative lateral displacement of the guide and the Stringerelements.

5. In a collapsible stairway, collapsible stringers comprising pivotallyconnected step and riser links, steps forming trusses with the steplinks and braces forming trusses with the riser links, and meansanchoring one end of said stairway, the opposite end of said stairwayadapted to rest against a suitable support.

6. In a collapsible stairway, lazy tongs stringers comprising step andriser links, steps connected to the step links at the crossing pivots ofthe links and at locations spaced from said pivots, and diagonalcrossing braces connected to said pivots and to outer pivots of thelazy-tongs assembly.

7. In a. collapsible stairway, lazy tongs stringers, steps connected tothe stringers, guides, and extensions from outer pivots of thelazy-tongs assembly, traveling in the respective guides.

l8. In a collapsible stairway, lazy tongs stringers, steps connected tothe stringers, guides, and extensions from outer pivots of thelazy-tongs assembly, traveling in the respective guides, a door, and asupport on which the door moves, said guides being carried on said doorand adjacent end links of the lazy-tongs structure being pivoted to saidsupport.

9. In a collapsible stairway, lazy tongs stringers, steps connected tothe stringers, guides, and extensions from outer pivots of the lazytongsassembly, traveling in the respective guides, a door, and a support onwhich the door moves, said guides being carried on said door andadjacent end links of the lazy-tongs structure being pivoted to saidsupport, certain links of said lazy-tongs stringers having projectionsat their ends opposite the ends having the guided pivot extensions,provided with engaging means, and engaging means on the support withwhich the link projecting engaging means engage to limit extension ofthe stringers.

10. In combination with a floor having an opening or hatchway, and atrap door hinged to one side of said hatchway to open downwardly, acollapsible stairway comprising pivotally connected elements, one ofwhich is pivoted to said side of the hatchway, and others of which havecertain pivotal connections movably connected to said door.

11. In a collapsible stairway structure, a lazytongs assembly of stepand riser links, and steps, each step having at each end a downturnedear connected to a respective crossing pivot of said links, and anupturned ear connected to the respective step link.

12. In a collapsible stairway structure, a lazytongs assembly of stepand riser links, steps, each step having at each end a downturned earconnected to a respective crossing pivot of said links, an upturned earconnected to the respective step link, and crossing diagonal braces,each having an ear at each end, one ear connected to a respective one ofsaid crossing pivots, and the other ear connected to a respective outerpivot that connects the riser link to a step link of an adjacent pair oflinks of the lazy-tongs assembly.

CLIFFORD TRAUT.

